• 한국토양비료학회지
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• 제49권4호
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• pp.300-309
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• 2016

The monolithic weighing lysimeter is a useful facility that could directly measure water movement via layers, drainage, and evapotranspiration (ET) with precise sensors. We evaluated water movement through layers and water balance using the lysimeter with undisturbed paddy sandy loam soil, Gangseo soil series (mesic family of Anthraquic Eutrudepts classified by Soil Taxonomy) during winter season from Dec. 2014 to Feb. 2015. Daily ET indicated up to 1.5 mm in December and January and 2 mm in February. The abrupt increase of soil water tension at the depth of 0.1 m, when soil temperature at the same depth was below $2^{\circ}C$, was observed due to temporary frost heaving. The surface evaporation was less than reference ET below -15 kPa of soil water potential at the depth of 0.1 m. The maximum drainage rate was similar to the saturated hydraulic conductivity of a plow pan layer. Both upward and downward water movement, related to ET and drainage, were retarded by a plow pan layer. This study demonstrated that the lysimeter study could well quantify water balance components even under frost heaving during winter season and that a plow pan with low permeability could act as a boundary that affects drainage and evapotranspiration.

• 농업과학연구
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• 제49권2호
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• pp.379-387
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• 2022

A large amount of the mineral nitrogen is necessary for crop growth. With the use of nitrogen fertilizers, agricultural yield has increased during the last few decades. However, at the same time, nitrate from the cultivated land can be a source of environmental pollution, especially in water systems. For nitrogen management, it is necessary to analyze the pattern of nitrogen movement in soil. In this study, nitrogen leaching in upland soils was evaluated using undisturbed lysimeters with different soil textures during sesame cultivation. The soil texture of the lysimeters was clay loam (Songjung series) and sandy loam (Sangju series) soils. Sesame was cultivated from May 25 to August 24 in 2020. The standard amount of NPK fertilizer (N-P₂O₅-K₂O = 2.9-3.1-3.2 kg·10 a^-1) was applied before sowing. The amount of nitrogen leaching was calculated by multiplying the nitrogen (NO₃-N + NH₄-N) concentration and the amount of water drained below 1.5 m soil depth. The water was drained through percolation into macropores in the clay loam lysimeter. In contrast, in the sandy loam lysimeter, water drained more slowly than in the clay loam lysimeter. There was a slight difference in the total amount of leachate during the cultivation period, but the amount of nitrogen leaching was high in sandy loam soil. During the sesame cultivation period, the amount of nitrogen leaching from clay soil was 5.64 kg·10 a^-1, and 10.70 kg·10 a^-1 for sandy soil. We found that there was a difference in leaching depending on the soil physical characteristics. Therefore, it is necessary to consider the characteristics of soil to evaluate the leaching of nitrogen.

• 한국환경농학회지
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• 제36권3호
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• pp.147-153
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• 2017

본 연구는 기상 조건 및 관개 여부가 양분용탈 및 콩의 양분 흡수에 영향을 미치는지 평가하기 위하여 중량식 라이시미터에서 2015년부터 2016년까지 콩을 재배한 결과를 제시하였다. 콩 재배기간인 6월부터 10월까지의 증발산량은 무관개구의 경우 강우에 따라 변동되었으며, 2016년 7월 중순부터 8월 말까지 지온상승 및 강우 빈도의 감소로 증발산량이 감소하다가 9월 중순 강우에 의해 유효수분 함량을 회복하여 생육 후기에 증발산량이 증가하였다. 질산태질소의 지하 용탈량은 2016년 7월 초 5일간 강우가 지속되었을 때 가장 많았으며, 그동안 지하배수가 거의 없었던 무관개구에서 더 높게 나타났다. 개화기 및 착협기인 7월 중순부터 8월까지 한발로 인하여 무관개구의 토양 수분함량은 7월 초의 50% 수준으로 유지되었으며, 콩 수량은 적습관개구의 25% 수준이었다. 적습관개구와 무관개구의 양분 흡수량을 비교한 결과 질소 흡수량이 적습관개구에서 20~50% 더 높았으며, 인산, 칼리 흡수량 차이는 미미하였다. 토양 수분함량은 콩의 질소 흡수에 영향을 미치며, 적정 수량을 생산하기 위해서는 관개를 통한 적정 수분 공급이 필수적이었다.

• 한국농공학회지
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• 제28권4호
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• pp.41-48
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• 1986

This study was fulfilled by the weighing lysimeter method at the experimental farm of KonKuk University from April to June of 1986 to investgate the amount of evapotranspiration ( ET-lettuec )by the growing periods, evapotranspiration ratio, amount of watering per one time, days of intermission and soil moisture extraction pattern of the crisphead lettuce cultivated in the clay loam soil by different watering points of pFl.7, pF2.O, pF2.7. The results obtained are summar ized as follows : 1.The total evapotranspiration(ETlettuce) of the pFl.7 treatment plot was 358,9mm., 314.9mm in the pF2.O plot and 281.8mm in the pF2.7 plot, therefore the total ETlettuec increased with the difference of 33mm-44mm by the decrease of watering point. 2.The daily maximum ETlettuce by the watering points was 7.66mm, 6:54mm, 5.98mm, respectively in the last ten days of May, and the mean daily ETlettuce during the growing season by the watering points of pFl.7, pF2.O and pF2.7 was 5.44mm(384.5g), 4.77mm(337.2g) and 4.27mm(301.8g), respectively. 3.The evapotranspiration ratio showed maximum value in the middle of May which was the beginning of mid-season stage, and the mean evapotranspiration ratio during the total growing period was 1A7, 1.29, 1.15 by the watering points. 4.The days of watering intermission by the watering points of pFl.7, pF2.O and pF2.7 was 1.0day, 2.9days and 12.Sdays, respectively. 5.The yield of the crisphead lettuce by the watering treatments showed very high significance, and the pF2.O was confirmed as a optimum watering point. 6.The soil moisture extraction pattern(SMEP) of the pF2.0 treatment plot in the initial stage was 85.6% in the 1st and 2nd soil layer and 14.4% in the 3rd and 4th layer, and in the midseason stage, the moisture extraction proportion of the under layer accounted for 34.7%which showed that the root elongated to the lowest soil layer, and there was no difference of the SMEP between the mid-season and late-season stage. 7.The correlation coefficient between the ETlettuce and yield of lettuce by the three watering points was.739, which showed the significance of 5%.

• 한국농림기상학회지
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• 제20권4호
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• pp.366-375
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• 2018

본 연구에서는 라이시미터를 이용하여 일천궁의 증발산량을 관측하였고, 그 자료를 분석하여 기상요소와 증발산량과의 관계를 조사하였다. 맑은 날이 지속된 4일간 라이시미터에서 관측된 증발산량은 일사량의 약 40%에 해당하는 것으로 관측되었으며, 증발산량 변화의 형태는 일출이 시작됨과 동시에 증가하였고 일몰과 함께 급격히 감소하여 일사량은 일천궁의 증발산량에 영향을 주는 중요한 인자로 나타났고 야간의 강한 풍속은 증발산량을 증가시켰으며, 일사량과 풍속이 증발산량 변화에 가장 큰 영향을 주는 요인이었다. $600W/m^2$ 이상의 일사량에서는 일천궁의 증발산량 증가가 없어 일천궁을 안정적으로 재배하기 위해서 잎 표면으로 입사되는 일사량의 조절이 필요한 것으로 조사되었다. 따라서 라이시미터는 야외에서 증발산량을 간단하면서도 정확하게 관측할 수 있는 방법임을 확인하였고, 추후 식물의 수분생리 및 적정 재배환경 구명에도 매우 유용할 것으로 사료된다.

• 한국작물학회지
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• 제53권2호
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• pp.161-170
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• 2008

Interest is growing in applying simulation models for the South Texas conditions, to better assess crop water use and production with different crop management practices. The Environmental Policy Integrated Climate (EPIC) model was used to evaluate its application as a decision support tool for irrigation management of com (Zea mays L.) in South Texas of the U.S. We measured actual crop evapotranspiration (ETc) using a weighing lysimeter, soil moisture using a neutron probe, and grain yield by field sampling. The model was then validated using the measured data. Simulated ETc using the Hargreaves-Samani equation was in agreement with the lysimeter measured ETc. Simulated soil moisture generally matched with the measured soil moisture. The EPIC model simulated the variability in grain yield with different irrigation regimes with $r^2$value of 0.69 and root mean square error of $0.5\;ton\;ha^{-1}$. Simulation results with farm data demonstrate that EPIC can be used as a decision support tool for com under irrigated conditions in South Texas. EPIC appears to be effective in making long term and pre-season decisions for irrigation management of crops, while reference ET and phenologically based crop coefficients can be used for inseason irrigation management.

• 한국토양비료학회지
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• 제32권4호
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• pp.344-356
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• 1999

토양수분 확산계수 추정을 위한 이론식(Mualem's principle)과 실측법(Hopmans' equation)을 제시하여 실험한 결과 실측치와 이론치의 상당한 근접을 보였으므로 Hopmans의 수치해석적 모형을 실측모형으로 재시하고자 한다. 작물계수 측정에 있어서는 생육시기에 따른 모형화보다는 생육온도에 따른 모형화가 함수 관계에 있어서 보다 더 유의성 있는 상관성을 보였다.

• 한국환경농학회지
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• 제37권3호
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• pp.166-171
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• 2018

중량식 라이시미터를 활용하여 배추 재배 중 식양토와 사양토의 질소 용탈과 질소 수지를 평가하였다. 생육 초기인 9월 초 강우로 인해 식양토와 사양토 모두 토심 150 cm 이하로 배수가 있었다. 식양토는 점토의 수축 및 작물 뿌리 등에 의해 형성된 대공극을 통해 일시적으로 배수량이 증가하였으나, 사양토는 식양토와 달리 강우량에 따라 일정하게 배수량이 증가하고, 감소하였다. 토성별로 질소 용탈량을 분석한 결과, 식양토에서는 비료의 용탈이 거의 없는 반면, 사양토에서는 식양토에 비해 5배 많은 질소 용탈이 있었다. 질소수지에서 작물 흡수량에 비해 질소 용탈량이 차지하는 비율은 적었으나 식양토에 비해 사양토에서의 용탈량이 많아 질소 수지 산정에 토성에 따른 용탈특성을 고려할 필요가 있다.

• 한국환경농학회지
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• 제42권3호
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• pp.211-219
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• 2023

중량식 라이시미터를 이용하여 사양질과 식질 토양에서 동계 작물인 청보리 재배 여부에 따른 양분 유출과 양분 수지를 평가하였다. 양분 유출과 관련된 지하 배수량은 식질에서 가장 많았으며, 동계 작물 재배 여부에 따른 토양 수분함량을 비교해보면 나지에서는 사양질과 식질 토양 모두 30-40%를 유지하였고, 청보리 재배구는 생육 재생기인 3-4월에 평균 증발산량이 평균 2.1-6.7 mm·day^-1이었으며, 토양 수분함량은 18.1-21.8%까지 낮아졌다. 동계작물 재배 시 봄철 생육재생기에 생체량이 증가함에 따라 증발산량도 증가하기 때문에 수분이 지상부로 이동하므로 양분의 지하유출을 예방할 수 있을 것으로 판단된다. 또한 사양질 토양에서 청보리의 재배에 따른 양분수지는 비료 공급량에 비해 작물 흡수량이 많아 음의 값을 나타냈으며, 토양에 집적된 양분을 이용했을 것으로 추측된다. 따라서 동계에 적정량의 비료를 주고 사료작물을 재배하면 경지 이용률을 높이고, 양분수지를 낮추는데 도움이 될 것으로 판단된다.

• 한국약용작물학회지
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• 제28권6호
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• pp.463-470
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• 2020

Background: Evaluation of transpiration is required for agricultural and environmental management applications, as crop yields and plant growth are primarily water limited. This study aimed to determine the transpiration and carbon accumulation of Cnidium officinale. Methods and Results: The transpiration of C. officinale was evaluated using weighing lysimeter. The relationship between transpiration and factors such as solar radiation, air temperature, and leaf area was assessed. Transpiration increased as the leaf area increased with the growth stage. Furthermore, daily transpiration per unit leaf area was 0.69 ± 0.16 g·cm-2·day-1 and there were no significant differences in daily transpiration during the cultivation period. The maximum transpiration was 620.6 g m-2·h-1 and diurnal changes in transpiration were highly correlated with solar radiation although the maximum transpiration was observed at the air temperatures of 20℃ - 26℃. The ratio of carbon accumulation to transpiration was 0.12%. Conclusions: Our results indicated that the transpiration of C. officinale is primarily regulated by solar radiation energy on clear days and that 97% of the water is discharged through transpiration for heat dissipation. Therefore, weighing lysimeters can measure transpiration accurately and may be useful in interpreting plant growth.